As a conventional motor of this kind, for example, one illustrated in PTL 1 is known.
Each of conductor segments in the motor illustrated in PTL 1 is obtained by forming a substantially rectangular-shaped conductor strand having a flat cross section into a substantially U shape, and a crank-shaped part without torsion is formed in the center part thereof. A conductor segment is inserted in slots formed in a stator core and is bent such that both end parts thereof are close to each other and the conductor segment makes a circle, and an end part is bonded to an end part of another adjacent conductor segment to form distribution winding by one conductor strand when electrically viewed, so that a stator winding is configured. The crank-shaped part of the conductor segment is formed to be overlapped with an adjacent conductor segment, more specifically, to be displaced by a width of the strand, and to have a length within a range of a distance between adjacent slots.
In this manner, the crank-shaped part of the conductor segment is formed to be displaced by the width of the strand, and not to generate torsion, so that the accuracy of overlap with an adjacent conductor segment can be increased, and therefore, a bulge of a stator in the radial direction in a coil end part of the stator winding, in which the crank-shaped part and the bonding part of the end parts are placed, can be suppressed.
In addition, as a stator having a stator winding configured by bonding end parts of a plurality of conductor segments, and a rotating electrical machine using the stator, for example, ones illustrated in PTL 2 are known.
A wire rod (conductor segment) for forming the stator winding in the rotating electrical machine illustrated in PTL 2 includes a pair of slot-housed parts to be placed in slots formed in a stator core and different in the circumferential direction, and turn parts that project toward the outside in the axis direction of the stator core from the slots and connect the pair of slot-housed parts to each other. A crank part without torsion is formed in the substantially center part of the turn parts. At projecting places of the turn parts that project toward the outside in the axis direction of the stator core from the slots, a pair of step parts that extends in parallel to an axis-direction end surface of the stator core from the respective pair of slot-housed parts is formed, and two step parts that extend in parallel to the axis-direction end surface of the stator core are formed between the crank part in the substantially center part and each of the pair of step parts.
In this manner, at the projecting places of the turn parts that project toward the outside in the axis direction of the stator core from the slots, the pair of step parts that extends in parallel to the axis-direction end surface of the stator core from the respective pair of slot-housed parts is formed, and thus, a distance between the projecting places of the turn parts is narrower than a distance between the slots in which the wire rod is placed. Accordingly, the shape of the wire rod that projects from the stator core becomes small, and a coil end height (a projecting height of the wire rod from the axis-direction end surface of the stator core) can be reduced.
In addition, the turn parts are formed in a staircase pattern having a plurality of step parts that extends in parallel to the axis-direction end surface of the stator core, and thus, the coil end height can be more suppressed by the plurality of step parts.